AUTOMOBILE 



517 



AUTOMOBILE 



C O:N T i N U O 



US IP O W 





PS 



PS 



PS 



PS 



C 



LJ 

 L-L 



LJ 



_J 



LJ 



_J 



d 



/POWER 



Q 



,/POWE 





Q 



GRAPHIC COMPARISON OP POWER 



or gas is drawn into the cylinder of the engine 

 by the suction of the piston, and when the 

 piston returns is compressed. Either just be- 

 fore or at the moment of greatest compression, 

 the mixture is ignited, thus causing the gas 

 to expand. The expanding gas drives back the 

 piston, the piston communicates power to a 

 crank shaft, and from the crank shaft through 



The above illustration graphically indicates the power produced by a six-cylinder and a four- 

 cylinder engine, and gives fuller explanation of the illustration above. It shows that the great- 

 re of a four is greater than that of the six; but the "six" produces continuous and 

 more nearly constant power, whereas in the "four" high pressure is followed by a moment of no 

 pressure at all. Shaded portion shows graphically the total pressure applied in a single cycle. 

 Both diagrams on same scale. 



Six-Cylinder (above): (o) highest pressure in a four whose power is equal that of a six; 

 (6) highest pressure in the "six"; (c) average pressure; (d) variations in actual pressure; (pa) 

 Indicates power stroke. 



ir-Cylinder (below): (b) highest pressure; (c) average pressure ; (d) variations in actual 

 ire; (pa) power stroke. 



these cylinders do not take place at the same 

 time, but one after another in regular succes- 

 sion. (See diagram.) It is obvious that the 

 more cylinders there are the greater is the 

 power of the car. 



Electric Automobiles. The electric automo- 

 bile owes its present development to Thomas 

 A. Edison. It differs from the steam and inter- 

 nal-combustion type in its essential feature; 

 it operates with power generated elsewhere and 

 stored in it, whereas the steam and gasoline en- 

 miies themselves generate the power which runs 

 them. The motive power in an electric auto- 

 mobile is furnished by a storage battery (which 

 see), which must be recharged from time to 

 lime. Places where electrical energy can be 

 easily obtained are usually limited to cities, 

 and a single i-hnr^e is sutliricnt for only sixty 

 to 100 miles. The speed of an electric automo- 

 bile is less than that of the gasoline type; it 

 seldom exceeds fifteen to twenty miles an 

 hour. On the other hand, it has the decided 

 advantage that it is cleaner, quieter and easier 

 to operate than a gasoline car; for these reasons 

 it has become a favorite for city use, especially 

 for women. 



The Automobile in War. Along with its 

 increasing usefulness in peace has been the 



A "SOCIAL ROADSTER" 



Before the year 1916 "roadsters" would seat 



hut tun j,.-.,j,],-. In that year models Heating 

 ami four were dewlmi. -I. i>\ .i.Miny a rear 

 eat wit I) narrow ftpace for the feet back of the 

 fn>nt neat and Hhortening the carrying apace In 

 the body over the rear wheels. 



an elaborate mechanism (called the transmis- 

 sion) to the wheels. For details of this proc- 

 ess see CARBURETOR; GAS ENGINE. The first 

 automobiles made had only one or two cylin- 

 ders. Later the Mimihrr \\a- increased to t 

 thru t.. M\. mlit and twelve. Explosions in 



